Runner for slide rules



Jan. 2; 1923. v1,440,915 C. F. IECKMANN RUNNER.FOR SLIDE RULES. FILEDrEB.25,192i.

HIIIIIIIIIIIIIE ATTKS? Patented Jan. 2, 1923.

UNITED STATES PATENTIoFFICI-z.

CARL F. DIECKMANN, OF CHICAGO, ILLINOIS, ASSIGNOR TO EUGENE DIETZGENCOMPANY, F CHICAGO, ILLINOIS, A CORPORATION 0F DELAWARE.

RUNNER FOR SLIDE RULES.

Application led February 25, 1921. Serial No. 447,713.

To all whmay t may concern:

Be it known that I, CARL F. DIECKMANN,

a citizen of the Ilnited States, residing at Chicago, in the county ofCook and State of Illinois, have invented a certain new and usefulImprovement in Runners for Slide Rules, of which the following is aspecification.

My invention relates to slide rules, and more particularly to therunners thereof. It is well known, of course, that the runners of sliderules have a reading line marked on the under side of a t-ransparentbody for enabling the user to read the diferent scales in making hiscomputations. Glass is often employed i'or the purpose, but slide rulesare frequently dropped orstrike against surrounding objects, thusbreaking the glass. It has been proposed to substitute (zelluloid, whichis not brittle, but celluloid has two disadvantages. It is not :is clearas glass and this Vlack of transparency makes it more diiicult to makethe readings accurately. A second disadvantage is that it scratches muchmore easily than glass and the surface soon becomes so abraded androughened as to make the readings diicult. The object of my invention isto produce a runner which Will have the advantages of glass in clearlyrevealing the reading line, and will at the same time possess adequatestrength and avoid the brittleness of glass.

I accomplish my object by the construction shown in the accompanyingdrawings, in which- Figure 1 is a top or face view of a runner embodyingmy invention, the same being shown in position upon a portion of a sliderule;

Figure 2 is an edge view of the parts shown in Figure 1.

Figure 3 is a sectional view on the line 3-3, Figure 1;

Figure 4; is a perspective view of the runner of the type shown inFigures 1 to 3.

y Figure 5 is a perspective view of a modified form of runner embodyingthe invention. and

Figure 6 is a sectional view on the line 6-6, Figure Like .numeralsdenote like parts throughout the several views.

First referring to the form shown in Figures 1 to et inclusive, theframe consists of under surface.

two channeled side bars l, having flanges 2 at the bottom adapted toslide in the grooves 3 in the edge of the slide rule 4l. It is desirableto provide a friction spring 6on the inside of one of the bars forretarding the sliding action of the runner and preventing the same frombeing accidentally displaced. f

.Extending across the rimner from one bar to the other, is a thin sheet8 of Celluloid which has the reading line 10 marked on its The sheet isso mounted that it lies close to but out of actual contact with theupper surface of the rule. While the thickness of this sheet may bevaried, it is desirable to make it quite thin; for illustration, about15/1000 of an inch. A sheet as thin as this is virtually as transparentas glass and the thickness may be considerably increased without greatlydecreasing the transparency.

Above this sheet of celluloid I mount a frame preferably of transparentor semitransparent material such as Celluloid, such frame having crossmembers 12 extending from one bar to the other and preferably integralwith longitudinal bars 137 which, however, preferably do not projectinward beyond the inner edges ofthe upper flanges 14 of the side bars.This frame performs two functions: First, it supplies the rigidity whichthe Celluloid sheet lacks, thus holding the side bars 1 properly spacedand with sufficient rigidity to frictionally engage the edges of therule. Second, as they are preferably four or five sixty-fourths of aninch thick and are only about three-fourths of an inch apart, they serveas a guard to prevent external objects from reaching the surface of thecelluloid and scratching it. In other words, the cross frame rigidifiesthe runner and protects the thin sheet of celluloid which carries thereading line.

In the form shown in Figures 1 to 4, the frame 12, 13 is originally aseparate piece from the Celluloid sheet, although it mav afterwards becemented to it. In the form shown in Figures 5 and 6, the frame andsheet are integral. The margins 16 are of the full thickness of theframefor example, four or five sixty-fourths of an inch or more, whilethe central portion 17 is hollowed down and thinned to such an eX- tentthat the reading line beneath may be readily apparent, A cross elementconstructeffl. in this Way ot a single piece has substantially the sameadvantages as the type first described, and it also has the advantage ofreducing the amount of time and workmanship required for nianuiiacture.

From the foregoing it `will be evident that as the centralv portion ofthe runner is thin, the reading line maybe distinctly seen- The rigidityis supplied by the thicker margins, which however, are `transparent to adegree making it possible to readily read the numbers marked on thescale. These numbers are larger and hence more easily read than the linescale markings and consequently the fact that the margins or' the runnerare somewhat less transparent than the center does not prevent thesenumbers from beingread. Furthermore it is only occasionallyv necessaryto read these scale numbers Where as the reading line is used for everycomputation. rlhus the runner is truly an open i'ace runner andpossesses the necessary ri.- gidity in addition to the fact that thecentral portion, Where'the reading line is located, is highlytransparent While the margins, although thicker, are rsudificientlj,7transparent for all practical purposes.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

il. A runner for slide rules comp rising)Y opposed U-shape side barsadapted to respectively receive between their arms opposite edges of theslide rule, a cross member oi.: transparent Celluloid between the barsand disposed at its sides beneath the upper arms of the bars, andelements at the ends ot the cross member raised above the centralportion of the upper surface thereof and serving in conjunction With theupper arms ot the bars to protect said surface or the CARL F. DIEUKMANN.

